2016 Update

Task/IBAN/Elixir/iban.elixir

@@ -0,0 +1,36 @@
+defmodule IBAN do
+  @len %{ AL: 28, AD: 24, AT: 20, AZ: 28, BE: 16, BH: 22, BA: 20, BR: 29,
+          BG: 22, CR: 21, HR: 21, CY: 28, CZ: 24, DK: 18, DO: 28, EE: 20,
+          FO: 18, FI: 18, FR: 27, GE: 22, DE: 22, GI: 23, GR: 27, GL: 18,
+          GT: 28, HU: 28, IS: 26, IE: 22, IL: 23, IT: 27, KZ: 20, KW: 30,
+          LV: 21, LB: 28, LI: 21, LT: 20, LU: 20, MK: 19, MT: 31, MR: 27,
+          MU: 30, MC: 27, MD: 24, ME: 22, NL: 18, NO: 15, PK: 24, PS: 29,
+          PL: 28, PT: 25, RO: 24, SM: 27, SA: 24, RS: 22, SK: 24, SI: 19,
+          ES: 24, SE: 24, CH: 21, TN: 24, TR: 26, AE: 23, GB: 22, VG: 24 }
+
+  def valid?(iban) do
+    iban = String.replace(iban, ~r/\s/, "")
+    if Regex.match?(~r/^[\dA-Z]+$/, iban) do
+      cc = String.slice(iban, 0..1) |> String.to_atom
+      if String.length(iban) == @len[cc] do
+        {left, right} = String.split_at(iban, 4)
+        num = String.codepoints(right <> left)
+              |> Enum.map_join(fn c -> String.to_integer(c,36) end)
+              |> String.to_integer
+        rem(num,97) == 1
+      else
+        false
+      end
+    else
+      false
+    end
+  end
+end
+
+[ "GB82 WEST 1234 5698 7654 32",
+  "gb82 west 1234 5698 7654 32",
+  "GB82 WEST 1234 5698 7654 320",
+  "GB82WEST12345698765432",
+  "GB82 TEST 1234 5698 7654 32",
+  "ZZ12 3456 7890 1234 5678 12"  ]
+|> Enum.each(fn iban -> IO.puts "#{IBAN.valid?(iban)}\t#{iban}" end)